MPs and protesters are stepping up their campaign against "extreme and disproportionate" sentences handed down to young Muslims involved in demonstrations against the Israeli invasion of Gaza last year.

There were 119 arrests after protests outside the Israeli embassy in London during which bottles and stones were thrown and a coffee shop was attacked.

Seventy-eight protesters were charged, most with violent disorder. So far 22 have been jailed for between eight months and two and half years, and more cases are due to come before the courts.

This week the families of those sentenced, the vast majority of whom are Muslim, met lawyers and MPs at the Commons to set out their concerns.

Jeremy Corbyn, the Labour MP for Islington North who chaired the meeting, said that the sentences amounted to an attack on the Muslim community and the right to protest.

He said: "Some of the sentences that have been handed down to these young demonstrators are extraordinary and out of all proportion to the crimes committed. What possible justification can there be for handing down a year in prison for a 19-year-old lad, studying dentistry, who threw a plastic bottle in the direction of the Israeli Embassy?"

Baroness Miller of Chilthorne Domer has tabled parliamentary questions about the policing of the event and the subsequent sentences.

She said: "There were a disproportionate number of people arrested and disproportionately severe sentences. I think people's right to protest should be recognised by the courts and I think they have not caught up with what is a new attitude to legitimate protest."

According to Crown Prosecution Service guidelines the maximum sentence for violent disorder is five years.

However, campaigners claim many of those sentenced should not have been charged with violent disorder and say the judge has repeatedly stated that the sentences were intended as a deterrent.

Joanne Gilmore, researcher in the School of Law at Manchester University, has monitored the cases and says people at more violent protests had received more lenient non-custodial, sentences.

"The vast majority of them were people of exemplary character, who were involved in the communities, caring for their families and often studying," she said. "The demonstrations were overwhelmingly peaceful and if you compare the relatively minor disturbances that took place with the violence on other demonstrations these sentences are very severe."

Gilmore said there were more arrests after the Gaza protests than at any political demonstration since the poll tax riots.

Campaigners say they are determined to fight the sentences. Corbyn is planning to table a motion in the Commons criticising the handling of the protesters, and families of those who have been locked up will meet lawyers to discuss appeals.